The present invention relates to automated article storage and retrieval systems in which articles are stored in bins, palettes or trays located within and along arrays of such trays, the trays are vertically spaced apart within recesses defined along the columnar arrays and are separated by an access region within which a platform is vertically and horizontally displaceable into registration with such array-supported trays or tray positions. More particularly, the invention is directed to a system having at least two such pairs of columnar arrays, each array in each pair confrontingly opposed with an access region therebetween, in which a single platform carrying a shuttle table is positioned to index/insert/extract bins from each array intra- or inter-each such array/pair such that the trays are selectively withdrawn from and inserted into the arrays by an indexing/insertion/extraction mechanism carried on the shuttle table. The indexing/insertion/extraction mechanism is also suitable for other, large scale systems in which bins are stored in arrays, including multiple confrontingly opposed columns in which the movable platform also moves in frontwards to backwards motion along a rail or other supporting member between groups of such confrontingly opposed columns.
Warehousing of articles has long been sought in order to achieve efficient use of space and inventory control. Many automated storage and retrieval systems provide high density storage with ready access to the stored articles. For example, commonly-invented U.S. Pat. No. 4,690,602 discloses a two-dimensional array of storage bins which are extractable for accessing stored articles by an extractor that moves down a center aisle between opposing arrays, locates the proper column of the array, moves upwardly or downwardly with respect to the column, and aligns with a proper bin location for extraction of a bin. The bin is thereafter extracted onto a platform, the platform with the bin carried thereupon is traversed to the front of the aisle, and the bin is presented for access to the articles stored therein.
In the ""602 patent, a two-dimensionally displaceable platform first traverses the aisle upon a rail without interference with the bins, and then extends arm-like extractor elements into the storage location past the front edge of a bin for engagement with the sides of the bin thereby providing withdrawal of the bin from the array, and similar reinsertion of the bin into the same or a different storage location.
Such multi-columnar arrays, while viable for the storage of a multiplicity of articles in light of the many locations for insertion and extraction of bins, create issues of complexity relative to the need for two-dimensional movement of the platform, and are thus typically not economically justifiable for smaller storage requirements.
Thus, an industry has developed that includes single, stand-alone units having a pair of confrontingly opposed columns for storage of bins, and a single platform that traverses the accessible region between the two columns. In such arrangements, the platform moves only in the single vertical dimension in the accessible region, by moving upwardly and downwardly. In such instances, extraction of bins from their respective locations in the columnar arrays is typically accomplished by either the use of fingers mounted to a single chain that catch a lip or extension mounted on the front of the bin (and back of the bin, respectively to allow full support and delivery), or by the use of opposing bars that are chain driven to catch such lips, as disclosed in commonly-invented U.S. Pat. No. 5,199,840. Since the platform for carrying the insertion/extraction mechanism in such stand-alone systems does not traverse a distance between multiple arrays, such a system does not include an ability to extend or index the mechanism into alignment, and to retract the mechanism to allow such additional traversal.
Insertion/extraction mechanisms found in the prior art, whether for large systems or stand-alone systems, typically employ fingers or bars that travel rotationally about a sprocket in order to extend into alignment with the lip or extension of the bin sought to be removed. Thus, the primary path of motion into alignment is rotational until the finger or bar is engaged. In these instances, sufficient distance must be created between vertically displaced bins such that the finger or bar, as it moves rotationally into alignment with the lip or extension of the bin to be extracted, does not collide with the bin positioned above or below. Thus the distance between bins in such arrangement is related to the radius of the circle traversed by the finger or pin about the sprocket that drives the finger or pin into alignment. Moreover, the same sprocket (with chain) assembly is both the driving force for engagement with the lip or extension, as well as for moving the finger or pin as the bin is extracted or inserted.
While large miniload systems offer too much storage space for certain applications, single, stand-alone units often offer too little. In these instances, customers generally purchase more than one stand-alone unit. The industry has heretofore failed to provide a system that enables the storage capacity of two (or more) stand-alone units, while having only a single platform conveyance system, motor drives, and controller. Thus, where purchasers buy more than one stand-alone unit, each has its own platform, motor drives and controller. In short, every item is merely duplicated.
In such stand-alone systems, like commonly invented U.S. Pat. No. 5,199,840 discussed above, the platform moves only in the vertical dimension, since the extractor must only access bins adjacent to the platform in the horizontal dimension. Thus, the ""840 patent requires the double-bar assembly to engage the front of a bin with its first bar, and substantially extract the bin onto the extractor until engagement by the second bar. No provision is made for accessing regions that are displaced in arrays adjacent to the two linearly confrontingly-opposed columns, nor would the apparatus function for such access.
It is thus an object of the instant invention to provide an indexing/insertion/extraction mechanism for use in large systems as well as smaller stand-alone systems that provides positive insertion and extraction and the ability to store at least twice the average number of bins of stand-alone systems by providing at least two pairs of confrontingly-opposed columns, while employing a single platform conveyor, drive mechanism, and controller.
The foregoing and other objects are achieved by the instant invention which involves a storage and retrieval system including at least two pairs of two confrontingly opposed, columnar arrays. Each of the pairs of columnar arrays defines a plurality of vertically spaced tray-receiving recesses, and an access region between the columns, in which an indexing/insertion/extraction mechanism is position for pulling bins or trays housed in the recesses. The mechanism has a platform vertically displaceable in the access regions between the pairs of arrays; a shuttle table rollably mounted upon the platform for horizontal displacement thereupon between the pairs of arrays; an extractor assembly supported by the shuttle table for causing horizontal insertion/extraction of bins onto the shuttle table, the assembly comprising a pair of endless chains each trained about first and second pairs of extractor sprockets, a drive rod positioned between one of the pairs of extractor sprockets, and two pairs of bin engagement fingers or two rods each traversing the distance between the endless chains for engaging the bin engagement members, such that as the drive rod is driven the bin engagement fingers or rods are caused to travel between and about the first and second pairs of extractor sprockets; a reducer having an input and output portions for indexingly engaging the extractor assembly for indexing the extractor assembly toward and away from the bins in gearingly synchronized sequence with the simultaneous driving of the pair of engagement rods, in which the reducer input portion is driven by a worm gear shaft and the reducer output portion in turn drives a linkage assembly; the worm gear shaft driven by a worm gear shaft sprocket and in turn driving a sprocket and chain assembly gearingly causing the simultaneous driving of the drive rod for the endless chains; the linkage assembly comprising a pivotally mounted pair of elongated members that pivot at three points of pivot, in which one of the members is attached at the first point of pivot to the reducer output portion of the reducer, the one of the members is attached at the second point of pivot to the second elongated member which in turn is attached at the third point of pivot to a vertical linkage shaft, such that as said reducer portion is caused to rotate, the rotation in turn causes circular rotation of the first elongated member and swinging rotation of the second member thereby linearly extending the linkage assembly from a smallest to largest distance dlinkage comprising the length of the first elongated member from the first to the second point of pivot and thereby indexing the extraction mechanism an index distance (d) from a neutral position do to a minimum/maximum distance xc2x1dlinkage; and a drive motor for causing the vertical linkage shaft to travel in a substantially straight-pathed groove in the shuttle table; and a single motor for cooperatively driving the indexing and movement of the bin engagement fingers or bars by chain engagement driving of the worm gear shaft sprocket. In this situation,
d=dlinkage sin Knt
where K represents a constant derived from sprocket size, chain length and reducer gear ratio, and nt is a movement of the engagement rods as a measured by the number of teeth moved by the sprockets, and further wherein:
xc2xd(nc/ns)=xc2xcnd
and nc is the number of teeth in the chain, ns is the number of teeth on the sprocket, and nd is the reducer gear ratio.
The double-bar assemblies of the prior art (as in, e.g., commonly-invented U.S. Pat. No. 5,199,840) cannot be used in anything but a rack assembly with two confrontingly-opposed columns. This is because the assembly cannot be shuttled over to another pair of columns, as in the instant invention. Consequently, in order to double the capacity of the prior art devices, more than one of the identical devices would have to be used. As a result, twice the controllers and twice the platforms and extractor mechanisms needed to be employed.
The instant invention overcomes the problem by use of a shuttle table rollably supported on a platform. In the preferred embodiment, a double pair of fingers are employed for insertion/extraction of bins. Alternatively, a double-bar extraction device can be employed. In either event, indexing is provided to allow the fingers or bars to engage the bins and pull/push them onto and off of the platform. Thus, the double-bar extraction mechanism of the past has been re-invented in a manner that provides that the first pair of fingers (or first bar) actually does not engage the bin handle, but rather passes by the bin handle as the entire mechanism is advanced/indexed into closer proximity, at which point the second pair of fingers (or second bar) engages. It can be observed that in distinction to the prior art devices, substantial withdrawal of the bin does not occur by way of the fingers or bars. Rather it occurs by way of the fingers (or bars) in combination with the indexer, and it is the indexer that completes the actual substantial removal or insertion of the bin.
Thus, it is observed that the gear ratios are important, as is the reducer and linkage assembly to accomplish synchronized movements. Such synchronization is also provided in a novel manner by use of only a single motor drive which drives a shaft attached to the reducer on its one side, and attached to a sprocket and driving assembly on the other for simultaneously driving the double-finger (or bar) assembly.
As a result, tight packing of bins can be achieved without the concern that spacing is a requirement for the bars to spin into alignment. Indeed, alignment now occurs by indexing. Likewise, much larger arrays can be handled either by increasing the length of the platform supporting the shuttle table, or rendering the platform on a stacker for miniload-type configurations. As customer needs continue to be improved and defined, this modular arrangement proves less expensive, since it possesses fewer components, and more modularly definable for customer needs, then multiple purchases and installations of the same stand-alone system.